Method for the production of metal sheet having a znmg or znalmg coating, comprising the application of a basic solution of a magnesium ion complexing agent, and resulting metal sheet.

Patent metadata

Field	Value
Publication number	US-2016010216-A1
Application number	US-201414768350-A
Country	US
Kind code	A1
Filing date	Feb 18, 2014
Priority date	Feb 18, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A method for the production of metal sheet including a substrate having two faces, at least one of which is coated with a metal coating including between 0.1 and 10% by weight of Mg and optionally between 0.1 and 20% by weight of Al, the remainder of the metal coating being Zn. The method includes at least the steps of providing a steel substrate having two faces, depositing a metal coating on at least one face hot dipping of the substrate, solidifying the metal coating, applying onto the outer surfaces of the metal coating an aqueous solution having a pH of 7 to 13 and including a magnesium ion complexing agent, for which the dissociation constant pKd of the complexing reaction of the agent with the magnesium is greater than or equal to 2, and to the metal sheet obtainable with this method.

First claim

What is claimed is:

1 - 22 . (canceled)

23 . A method for preparing a metal sheet comprising the steps of:
providing a substrate having two faces; depositing a metal coating on at least one face of the substrate by hot dipping the substrate, the metal coating including from 0.1 to 10% by weight of Mg, a remainder of the metal coating being Zn and inevitable impurities, solidifying the metal coating; applying on outer surfaces of the metal coating an aqueous solution with a pH from 7 to 13 including:
an agent complexing magnesium ions, for which a dissociation constant pKd of the complexing reaction with magnesium is greater than or equal to 2, and
less than 1 g/L of cobalt ions.

24 . The method according to claim 23 , wherein the aqueous solution has a pH from 7 to 11.5.

25 . The method according to claim 23 , wherein the aqueous solution is free of cobalt ions.

26 . The method according to claim 23 , wherein the aqueous solution has a pH from 7 to 11.5 and is free of cobalt ions.

27 . The method according to claim 23 , wherein the metal coating includes from 0.3 to 10% by weight of magnesium.

28 . The method according to claim 27 , wherein the metal coating includes from 0.3 to 4% by weight of magnesium.

29 . The method according to claim 43 , wherein the metal coating includes from 0.5 to 11% by weight of aluminum.

30 . The method according to claim 29 , wherein the metal coating includes from 0.7 to 6% by weight of aluminum.

31 . The method according to claim 30 , wherein the metal coating includes from 1 to 6% by weight of aluminum.

32 . The method according to claim 23 , wherein a mass ratio between the magnesium and the aluminum in the metal coating is less than or equal to 1.

33 . The method according to claim 23 , wherein the agent complexing magnesium ions is selected from glycine, pyrophosphoric acid, triphosphoric acid, citric acid, oxalic acid, diamino cyclohexane tetraacetic acid, diethylenetriamine pentacetic acid, ethylenediaminetetraacetic acid and nitrilotriacetic acid, in a neutral or salt form, and a mixture thereof.

34 . The method according to claim 33 , wherein the agent complexing magnesium ions is selected from glycine, pyrophosphoric acid, diamino cyclohexane tetraacetic acid, diethylenetriamine pentacetic acid, ethylenediaminetetraacetic acid and nitrilotriacetic acid, in neutral or salt form, and a mixture thereof.

35 . The method according to claim 34 , wherein the agent complexing magnesium ions is selected from glycine, diamino cyclohexane tetraacetic acid, diethylenetriamine pentacetic acid, ethylenediaminetetraacetic acid and nitrilotriacetic acid, in neutral or salt form, and a mixture thereof.

36 . The method according to claim 35 , wherein the agent complexing magnesium ions is glycine or one of its salts.

37 . The method according to claim 23 , wherein the aqueous solution includes from 1 to 300 g/L of the agent complexing magnesium ions.

38 . The method according to claim 23 , wherein the aqueous solution has a pH from 9 to 11.

39 . The method according to claim 38 , wherein the aqueous solution has a pH from 9 to 10.

40 . The method according to claim 1 , wherein the aqueous solution is applied at a temperature from 20 to 70° C.

41 . The method according to claim 1 , wherein the aqueous solution is applied for a duration from 0.5 s to 40 s on the outer surfaces of the metal coating.

42 . A metal sheet having two faces, at least one of which is coated with a metal coating comprising between 0.1 and 10% by weight of Mg and optionally between 0.1 and 20% by weight of Al, the remainder being Zn, the inevitable impurities and optionally one or several additional elements selected from Si, Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Cr, Ni or Bi, obtainable by a method according to claim 1 .

43 . The method according to claim wherein there the metal coating includes from 0.1 to 20% by weight of Al.

44 . The method according to claim wherein there the metal coating includes at least one of Si, Sb, Pb, Ti, Ca, Mn, Sn, La, Ce, Cr, Ni or Bi.

Assignees

• Arcelormittal

Inventors

• Allely Christian
• Machado Amorim Tiago
• Coffigny Astrid

Classifications

• C23C22/60

  using alkaline aqueous solutions with pH greater than 8 · CPC title

• C23C2/06 Primary

  Zinc or cadmium or alloys based thereon · CPC title

• C23G1/20

  Other heavy metals · CPC title

• C23C28/321 Primary

  with at least one metal alloy layer · CPC title

• B32B15/013

  one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium · CPC title